This invention relates to the art of welding and, more particularly, to the encoding of metal welding wire with information pertaining thereto, and to the control of automatic or semi-automatic welding apparatus and processes based on the information extracted from a coded welding wire or from other electronically readable information storage devices encoded with information pertaining to a given welding wire.
The present invention is particularly applicable to the encoding and use of coded filler wire and other electronically readable information storage devices in connection with controlling automatic or semiautomatic arc welding apparatus and processes based on information pertaining to the welding wire. Accordingly, the invention will be described with reference to such welding wire information and the storage and use thereof in conjunction with manual and/or automatic control of a welding process or apparatus. Incorporated herein by reference for background information is U.S. Pat. No. 5,692,700 to Bobeczko which is assigned to the assignee of the present application and which discloses the provision of a bar code on a cover and/or reel to identify the type and size of the welding wire on the reel.
Electric arc welding is a complicated process wherein numerous interrelated and non-interrelated parameters affect the deposition of molten metal to a weld pool in performing a welding operation. One such parameter is the welding wire to be used and, in particular, information pertaining thereto which is useful, for example, in determining processes and apparatus in which its use is best suited and processes and/or apparatus operating parameters for a given wire. Other information, such as the date and time of manufacture, the manufacturing location and the like, can assist in tracing the origin of the wire should a problem occur requiring contact with the manufacturer. Further, information such as the alloy type, wire diameter, control numbers, lubrication levels, and the like is valuable for controlling a given process or apparatus so as to optimize performance and weld quality.
In particular, the quality of automated welding is significantly affected by variations in the welding wire diameter which can vary by +/-0.001 inch and still be within welding wire specifications, and such a variation can change the deposition rate by as much as six percent for 0.035 inch diameter wire. Welding wire is drawn, and such diameter variations result from a manufacturer's efforts to fully extend the life of a die by starting with a die that produces slightly undersized wire within a given specification. The die progressively wears during production, whereby the wire size gradually increases and eventually becomes oversized with respect to the specification. While it is possible to tightly control the wire diameter during production such as by frequent replacement of dies, such production for most practical purposes is economically unacceptable. Another major factor affecting weld quality is a variation in the proportion of major to minor gases in the shielding gas mixture for GMAW or MIG welding. The variation of the proportion of the minor gas from a given standard therefore can significantly alter the heat input and thus the weld size, shape and quality.